The recent violence at the border between Serbia and northern Kosovo brought to a head what could be the biggest stumbling block for Serbia in its bid for European Union membership. The United Nations Security Council this week condemned the violence, but refused Serbia’s wish to implicate Kosovo in provoking the conflict. Pressure on Serbian leaders is mounting.

The flareup of violence in northern Kosovo in late July was the worst in several years. It left one police officer dead and many civilians injured.

German Chancellor Angela Merkel responded to the clashes by saying the European Union believed such events were in the past.

Weeks later, Merkel turned up the heat even further, calling on Belgrade to abolish its institutions in northern Kosovo and allow the EU’s law and justice mission [EULEX] to operate freely there. She linked these conditions to Serbia’s EU candidacy bid.

This was the first time most Serbs had heard these conditions. Coming on the heels of the recent violence, and following Serbia’s long-sought transfer of two war crimes suspects to the Hague tribunal, the possibility of not getting EU candidacy took people by surprise.

Serbia has been working for years to join the EU, and the European Commission is set to make its recommendation for candidate status in October.

Maja Bobic is head of the European Movement in Serbia, which promotes democratic values and EU integration.

"Maybe it was also the timing and maybe it was also that we heard on a number of occasions during this entire year that after fulfilling this most important and prominent condition, which is cooperation with the Hague tribunal, and of course continuing the reforms, internal reform, that candidate status was something that is almost guaranteed," said Bobic. "This was something we could hear also from European officials. It was taken for granted that candidate status was something that Serbia will have in this year."

President Boris Tadic said that Belgrade will not abolish its northern Kosovo institutions. He said Serbia is open to the EU mission in the entire territory, and there is room for compromise.

But he also acknowledged for the first time the possibility that Serbia might not get its EU candidate status this year.

Other Serb leaders followed suit.

Minister for Kosovo Goran Bogdanovic told Serbian media that he had the thankless task to say that Serbia would stick to its institutions even if that “blocked Serbia’s European path.”

At the U.N., Serbian Foreign Minister Vuk Jeremic urged the international community to condemn Kosovo for the violent escalation. He was defiant about Serbia’s nationalist claim on Kosovo.

"I would like to once again reaffirm my government's position on Pristina's attempt at unilateral secession from Serbia. We do not, and we shall not, recognize it explicitly or implicitly," said Jeremic. "This is mandated by the democratic will of our people and enshrined in our constitution."

Serbian leaders realize that Belgrade is not being asked to formally recognize Kosovo’s independence - rather to normalize relations. But many see these demands as de-facto recognition, something Serbian politicians believe their constituents will never accept.

Bosko Jaksic, a columnist for the Serb newspaper Politika, said Kosovo is already lost to Serbia. He said Serb politicians fear that betraying their nationalist base will cost them in upcoming elections.

"Most of the Serbs are realizing that Kosovo is not Serbia anymore. And I think the politicians are not stupid that they don't realize themselves the same thing. I would tell them to face the nation, to say 'yes, we have your support to get Serbia into the European Union and we are going to do it.' The price for it is normalizing relations with Kosovo," said Jaksic.

Chancellor Merkel appeared Tuesday in Slovenia where reports said she had softened her stance, saying a gradual approach could be used in Kosovo.

European parliament member Doris Pack told Voice of America this week, however, that the European Union cannot accept a nation in conflict with its neighbor.

Belgrade must demonstrate that it is serious about moving forward in negotiations with Kosovo. “We need proof that they are willing,” she said.